Wind tunnel experiments on a NACA0015 airfoil equipped with vectorizable dielectric barrier discharge plasma actuators

This work reports an experimental investigation performed in wind tunnel facility on a NACA0015 airfoil equipped with a set of vectorizable fluid-dynamic DBD plasma actuators. The ability of the actuators to recover the stall condition with free stream velocities in the range 5-23 m/s has been investigated. The discharge has been generated by feeding the actuators with a sinusoidal voltage waveform with a frequency of 15 kHz and voltages up to 7.5 kV peak. The actuator positioned on the leading edge exhibits highest ability in the stall recovery. Unsteady actuation obtained by alternatively switching on and off the discharge is more effective in the stall recovery when compared with a steady actuation. The frequency that optimizes the stall recovery has been found to be a function of the velocity with the power of 1.5. This result leads to the determination of a constant Strouhal number if the boundary layer thickness is used as characteristic length. Finally the lift coefficient, obtained when the plasma actuator has been turned on, has been found to be a linear function of the applied voltage.